/**
 * Copyright (c) 2005-2011 springside.org.cn
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * 
 * $Id: HibernateDao.java 1547 2011-05-05 14:43:07Z calvinxiu $
 */
package org.guess.core.orm.hibernate;

import java.io.Serializable;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

import org.apache.commons.lang3.ArrayUtils;
import org.apache.commons.lang3.StringUtils;
import org.guess.core.orm.Page;
import org.guess.core.orm.PageRequest;
import org.guess.core.orm.PageRequest.Sort;
import org.guess.core.orm.PropertyFilter;
import org.guess.core.orm.PropertyFilter.MatchType;
import org.guess.core.utils.AssertUtils;
import org.guess.core.utils.ReflectionUtils;
import org.hibernate.Criteria;
import org.hibernate.Query;
import org.hibernate.criterion.CriteriaSpecification;
import org.hibernate.criterion.Criterion;
import org.hibernate.criterion.Disjunction;
import org.hibernate.criterion.MatchMode;
import org.hibernate.criterion.Order;
import org.hibernate.criterion.Projection;
import org.hibernate.criterion.Projections;
import org.hibernate.criterion.Restrictions;
import org.hibernate.internal.CriteriaImpl;
import org.hibernate.transform.ResultTransformer;

import com.google.common.collect.Maps;

/**
 * 封装SpringSide扩展功能的Hibernat DAO泛型基类.
 * 
 * 扩展功能包括分页查询,按属性过滤条件列表查询.
 * 
 * @param <T>
 *            DAO操作的对象类型
 * @param <ID>
 *            主键类型
 * 
 * @author calvin
 * @author guess
 */
@SuppressWarnings({ "unchecked", "rawtypes" })
public class HibernateDao<T, ID extends Serializable> extends
		SimpleHibernateDao<T, ID> {

	public static final String DEFAULT_ALIAS = "x";

	/**
	 * 通过子类的泛型定义取得对象类型Class. eg. public class UserDao extends HibernateDao<User,
	 * Long>{ }
	 */
	public HibernateDao() {
		super();
	}

	public HibernateDao(Class<T> entityClass) {
		super(entityClass);
	}

	// -- 分页查询函数 --//

	/**
	 * 分页获取全部对象.
	 */
	public Page<T> getAll(final PageRequest pageRequest) {
		return findPage(pageRequest);
	}

	/**
	 * 按HQL分页查询.
	 * 
	 * @param pageRequest
	 *            分页参数.
	 * @param hql
	 *            hql语句.
	 * @param values
	 *            数量可变的查询参数,按顺序绑定.
	 * 
	 * @return 分页查询结果, 附带结果列表及所有查询输入参数.
	 */
	public Page<T> findPage(final PageRequest pageRequest, String hql,
			final Object... values) {
		AssertUtils.notNull(pageRequest, "pageRequest不能为空");

		Page<T> page = new Page<T>(pageRequest);

		if (pageRequest.isCountTotal()) {
			long totalCount = countHqlResult(hql, values);
			page.setTotalItems(totalCount);
		}

		if (pageRequest.isOrderBySetted()) {
			hql = setOrderParameterToHql(hql, pageRequest);
		}
		Query q = createQuery(hql, values);

		setPageParameterToQuery(q, pageRequest);

		List result = q.list();
		page.setResult(result);
		return page;
	}

	/**
	 * 按HQL分页查询.
	 * 
	 * @param page
	 *            分页参数.
	 * @param hql
	 *            hql语句.
	 * @param values
	 *            命名参数,按名称绑定.
	 * 
	 * @return 分页查询结果, 附带结果列表及所有查询输入参数.
	 */
	public Page<T> findPage(final PageRequest pageRequest, String hql,
			final Map<String, ?> values) {
		AssertUtils.notNull(pageRequest, "page不能为空");

		Page<T> page = new Page<T>(pageRequest);

		if (pageRequest.isCountTotal()) {
			long totalCount = countHqlResult(hql, values);
			page.setTotalItems(totalCount);
		}

		if (pageRequest.isOrderBySetted()) {
			hql = setOrderParameterToHql(hql, pageRequest);
		}

		Query q = createQuery(hql, values);
		setPageParameterToQuery(q, pageRequest);

		List result = q.list();
		page.setResult(result);
		return page;
	}

	/**
	 * 按Criteria分页查询.
	 * 
	 * @param page
	 *            分页参数.
	 * @param criterions
	 *            数量可变的Criterion.
	 * 
	 * @return 分页查询结果.附带结果列表及所有查询输入参数.
	 */
	public Page<T> findPage(final PageRequest pageRequest,
			final Criterion... criterions) {
		AssertUtils.notNull(pageRequest, "page不能为空");

		Page<T> page = new Page<T>(pageRequest);

		Criteria c = createCriteria(criterions);

		if (pageRequest.isCountTotal()) {
			long totalCount = countCriteriaResult(c);
			page.setTotalItems(totalCount);
		}

		setPageRequestToCriteria(c, pageRequest);

		List result = c.list();
		page.setResult(result);
		return page;
	}

	/**
	 * 在HQL的后面添加分页参数定义的orderBy, 辅助函数.
	 */
	protected String setOrderParameterToHql(final String hql,
			final PageRequest pageRequest) {
		StringBuilder builder = new StringBuilder(hql);
		builder.append(" order by");

		for (Sort orderBy : pageRequest.getSort()) {
			builder.append(String.format(" %s.%s %s,", DEFAULT_ALIAS,
					orderBy.getProperty(), orderBy.getDir()));
		}

		builder.deleteCharAt(builder.length() - 1);

		return builder.toString();
	}

	/**
	 * 设置分页参数到Query对象,辅助函数.
	 */
	protected Query setPageParameterToQuery(final Query q,
			final PageRequest pageRequest) {
		q.setFirstResult(pageRequest.getOffset());
		q.setMaxResults(pageRequest.getPageSize());
		return q;
	}

	/**
	 * 设置分页参数到Criteria对象,辅助函数.
	 */
	protected Criteria setPageRequestToCriteria(final Criteria c,
			final PageRequest pageRequest) {
		AssertUtils.isTrue(pageRequest.getPageSize() > 0,
				"Page Size must larger than zero");

		c.setFirstResult(pageRequest.getOffset());
		c.setMaxResults(pageRequest.getPageSize());

		if (pageRequest.isOrderBySetted()) {
			for (Sort sort : pageRequest.getSort()) {
				if (Sort.ASC.equals(sort.getDir())) {
					c.addOrder(Order.asc(sort.getProperty()));
				} else {
					c.addOrder(Order.desc(sort.getProperty()));
				}
			}
		}
		return c;
	}

	/**
	 * 执行count查询获得本次Hql查询所能获得的对象总数.
	 * 
	 * 本函数只能自动处理简单的hql语句,复杂的hql查询请另行编写count语句查询.
	 */
	protected long countHqlResult(final String hql, final Object... values) {
		String countHql = prepareCountHql(hql);

		try {
			Long count = findUnique(countHql, values);
			return count;
		} catch (Exception e) {
			throw new RuntimeException("hql can't be auto count, hql is:"
					+ countHql, e);
		}
	}

	/**
	 * 执行count查询获得本次Hql查询所能获得的对象总数.
	 * 
	 * 本函数只能自动处理简单的hql语句,复杂的hql查询请另行编写count语句查询.
	 */
	protected long countHqlResult(final String hql, final Map<String, ?> values) {
		String countHql = prepareCountHql(hql);

		try {
			Long count = findUnique(countHql, values);
			return count;
		} catch (Exception e) {
			throw new RuntimeException("hql can't be auto count, hql is:"
					+ countHql, e);
		}
	}

	private String prepareCountHql(String orgHql) {
		String countHql = "select count (*) "
				+ removeSelect(removeOrders(orgHql));
		return countHql;
	}

	private static String removeSelect(String hql) {
		int beginPos = hql.toLowerCase().indexOf("from");
		return hql.substring(beginPos);
	}

	private static String removeOrders(String hql) {
		Pattern p = Pattern.compile("order\\s*by[\\w|\\W|\\s|\\S]*",
				Pattern.CASE_INSENSITIVE);
		Matcher m = p.matcher(hql);
		StringBuffer sb = new StringBuffer();
		while (m.find()) {
			m.appendReplacement(sb, "");
		}
		m.appendTail(sb);
		return sb.toString();
	}

	/**
	 * 执行count查询获得本次Criteria查询所能获得的对象总数.
	 */
	protected long countCriteriaResult(final Criteria c) {
		CriteriaImpl impl = (CriteriaImpl) c;

		// 先把Projection、ResultTransformer、OrderBy取出来,清空三者后再执行Count操作
		Projection projection = impl.getProjection();
		ResultTransformer transformer = impl.getResultTransformer();

		List<CriteriaImpl.OrderEntry> orderEntries = null;
		try {
			orderEntries = (List) ReflectionUtils.getFieldValue(impl,
					"orderEntries");
			ReflectionUtils
					.setFieldValue(impl, "orderEntries", new ArrayList());
		} catch (Exception e) {
			logger.error("不可能抛出的异常:{}", e.getMessage());
		}

		// 执行Count查询
		Long totalCountObject = (Long) c.setProjection(Projections.rowCount())
				.uniqueResult();
		long totalCount = (totalCountObject != null) ? totalCountObject : 0;

		// 将之前的Projection,ResultTransformer和OrderBy条件重新设回去
		c.setProjection(projection);

		if (projection == null) {
			c.setResultTransformer(CriteriaSpecification.ROOT_ENTITY);
		}
		if (transformer != null) {
			c.setResultTransformer(transformer);
		}
		try {
			ReflectionUtils.setFieldValue(impl, "orderEntries", orderEntries);
		} catch (Exception e) {
			logger.error("不可能抛出的异常:{}", e.getMessage());
		}

		return totalCount;
	}

	// -- 属性过滤条件(PropertyFilter)查询函数 --//

	/**
	 * 按属性查找对象列表,支持多种匹配方式.
	 * 
	 * @param matchType
	 *            匹配方式,目前支持的取值见PropertyFilter的MatcheType enum.
	 */
	public List<T> findBy(final String propertyName, final Object value,
			final MatchType matchType) {
		Criterion criterion = buildCriterion(propertyName, value, matchType);
		return find(criterion);
	}

	/**
	 * 按属性过滤条件列表查找对象列表.
	 */
	public List<T> find(List<PropertyFilter> filters) {
		Criterion[] criterions = buildCriterionByPropertyFilter(filters);
		return find(criterions);
	}

	/**
	 * 按属性过滤条件列表分页查找对象. 增加联级查询
	 */
	public Page<T> findPage(final PageRequest pageRequest, final List<PropertyFilter> filters) {
		AssertUtils.notNull(pageRequest, "page不能为空");
		Criterion[] criterions = buildCriterionByPropertyFilter(filters);
		return findPage(pageRequest,criterions,filters);
	}
	
	/**
	 * 增加or查询
	 */
	public Page<T> findPage(final PageRequest pageRequest, final List<PropertyFilter> filters, final List<PropertyFilter> orfilters) {
		AssertUtils.notNull(pageRequest, "page不能为空");
		Criterion[] criterions = buildCriterionByPropertyFilter(filters);
		Criterion[] orcriterions = buildOrCriterionByPropertyFilter(orfilters);
		filters.addAll(orfilters);
		return findPage(pageRequest,ArrayUtils.addAll(criterions, orcriterions),filters);
	}
	

	/**
	 * 扩展
	 */
	public Page<T> findPage(final PageRequest pageRequest,Criterion[] criterions, final List<PropertyFilter> filters) {
		Page<T> page = new Page<T>(pageRequest);
		Criteria c = createCriteria(criterions);
		Map<String, String> alias = Maps.newHashMap();
		for (PropertyFilter filter : filters) {
			if (!filter.hasMultiProperties()) {
				if (filter.getPropertyName().indexOf(".") != -1) {
					String objName = StringUtils.substringBefore(
							filter.getPropertyName(), ".");
					alias.put(objName, objName);
				}
			} else {
				for (String param : filter.getPropertyNames()) {
					if (param.indexOf(".") != -1) {
						String objName = StringUtils
								.substringBefore(param, ".");
						alias.put(objName, objName);
					}
				}
			}
		}

		for (String key : alias.keySet()) {
			c.createAlias(key, alias.get(key));
		}

		if (pageRequest.isCountTotal()) {
			long totalCount = countCriteriaResult(c);
			page.setTotalItems(totalCount);
		}

		setPageRequestToCriteria(c, pageRequest);

		List result = c.list();
		page.setResult(result);
		return page;
	}
	

	/**
	 * 按属性条件参数创建Criterion,辅助函数.
	 */
	protected Criterion buildCriterion(final String propertyName,
			final Object propertyValue, final MatchType matchType) {
		AssertUtils.hasText(propertyName, "propertyName不能为空");
		Criterion criterion = null;
		// 根据MatchType构造criterion
		switch (matchType) {
		case EQ:
			criterion = Restrictions.eq(propertyName, propertyValue);
			break;
		case LIKE:
			criterion = Restrictions.like(propertyName, (String) propertyValue,
					MatchMode.ANYWHERE);
			break;

		case LE:
			criterion = Restrictions.le(propertyName, propertyValue);
			break;
		case LT:
			criterion = Restrictions.lt(propertyName, propertyValue);
			break;
		case GE:
			criterion = Restrictions.ge(propertyName, propertyValue);
			break;
		case GT:
			criterion = Restrictions.gt(propertyName, propertyValue);
		}
		return criterion;
	}

	/**
	 * 按属性条件列表创建Criterion数组,辅助函数.
	 */
	protected Criterion[] buildCriterionByPropertyFilter(
			final List<PropertyFilter> filters) {
		List<Criterion> criterionList = new ArrayList<Criterion>();
		for (PropertyFilter filter : filters) {
			if (!filter.hasMultiProperties()) { // 只有一个属性需要比较的情况.
				Criterion criterion = buildCriterion(filter.getPropertyName(),
						filter.getMatchValue(), filter.getMatchType());
				criterionList.add(criterion);
			} else {// 包含多个属性需要比较的情况,进行or处理.
				Disjunction disjunction = Restrictions.disjunction();
				for (String param : filter.getPropertyNames()) {
					Criterion criterion = buildCriterion(param,
							filter.getMatchValue(), filter.getMatchType());
					disjunction.add(criterion);
				}
				criterionList.add(disjunction);
			}
		}
		return criterionList.toArray(new Criterion[criterionList.size()]);
	}
	
	/**
	 * 按属性创建orCriterion数组,辅助函数.
	 * @param orfilters
	 * @return
	 */
	protected Criterion[] buildOrCriterionByPropertyFilter(List<PropertyFilter> orfilters) {
		List<Criterion> criterionList = new ArrayList<Criterion>();
		Disjunction disjunction = Restrictions.disjunction();
		for (PropertyFilter filter : orfilters) {
			if (!filter.hasMultiProperties()) { // 只有一个属性需要比较的情况.
				Criterion criterion = buildCriterion(filter.getPropertyName(),
						filter.getMatchValue(), filter.getMatchType());
				disjunction.add(criterion);
			} else {// 包含多个属性需要比较的情况,进行or处理.
				for (String param : filter.getPropertyNames()) {
					Criterion criterion = buildCriterion(param,
							filter.getMatchValue(), filter.getMatchType());
					disjunction.add(criterion);
				}
			}
			criterionList.add(disjunction);
		}
		return criterionList.toArray(new Criterion[criterionList.size()]);
	}
}
